Focusing means for cameras



v. E. PRATT 2,383,161

FOCUSING MEANS FOR CAMERAS 7 Original Filed Jan. 3, 1942 4 Sheets-Sheet 1 Aug. 21, 1945.

INVENTOR VERA/EUR E. PM T7.

jwm+% ATTORNEYS 1945- v E. PRATT FOCUSING MEANS FOR CAMERAS 4 Sheets-Sheet 2 Original Filed Jan. 5, 1942 M R m5 m H N n W WM+M ATTORNEYS Aug. 21, 1945; v P'RA T 2,383,161

FOCUSING MEANS FOR CAMERAS Original Filed Jan. 3, 1942 4 Sheets-Sheet 3 1 /7r /79 may SHUTTER F76. 7

ELEVATOR FOCUS E NLARGER INVENTOR java F761 9 I 'BYVERNEUR .PRATT ATTORNEYS Aug. 21, 1945. E PRATT 2,383,161

FOCUSING MEANS FOR CAMERAS Original Filed Jan. 5, 1942 4 Sheets-Sheet 4 INVENTOR KER/V501? E. FHA 77- ATTORNEYS Patented Aug. 21, 1945 v UNITED rocusmc MEANS FOR CAMERAS Verneur E. Pratt, Norwalk, Comm, m a

Microstat Corporation, a corporation of Delaware Original application January 3,1942, Serial No. 425,528. Divided and this application July 1,

1943, Serial No. 493,036

4 Claims.

The present invention pertains to improvements in focusing means for cameras.

This application is a division of copendins application Serial No. 425,528, flied January 3, 1942, now Patent No. 2,369,247, of February 13, 1945. The principal object of the invention is the provision, in a camera, for recording drawings, maps, documents and the like on photographic film such as microfilm, of a lens, controlled by a reversible motor through positiv speed reducing means, to a rotary focusing means on said lens and a counter positively operable by said motor, said counter having visual characters indicating predetermined increments of movement of said lens. Another object of the invention is the provision of a camera having a lens moved therein on the line of the optical axis, rotary means to move the lens on said line and motor means controlled from a point spaced apart from said lens for moving the lens toward or away from its focal plane in said camera, and means positively connected to said motor and carrying vis- Figure 2 is a perspective detail view of the camera-projector and its mounting;

Figure 3 is a vertical side view of the camera-' projector and related apparatus partly in section;

Figure 4 is a detail view of the elevation indicating scale; e I

Figure 5 is a detail view of the exposure motor holding switch and cam;

Figure 6 is a similar view of the cam and switch for controlling open. shutter warning light during picture takin8;

platen or table 84 is adjustablysecui ed to the k being shown in enlarged perspective Figure 7 is a detail view of the main operational control panel and apparatus;

Figure 8 is a similar view of the main switching and illumination control paneli Figure 9 is a sectional detail view showing the disposal of the illumination control means;

Figure 10 illustrates the foot-switch for tripping the exposure motor; and

Figure 11 is a wiring diagram of the various electrical apparatus embodied in the invention.

Referring to Figure l, a stiff triangular frame 30, preferably of welded steel construction, is mounted on supporting legs ii, I! and N. A

top of the frame I0. Twoauxiliaryl supporting columns, provided with heavy bases 31 and 138, are disposed under the front corners of the table N. Suitable clearance is normally provided between the upper ends 39 of these columns and the, table as shown in Figure 9. l

Rigidly secured in the rear of theirs-me is g a vertical tubular column 40 onwhich is slidab'ly mounted a bracket or carriage l l. The bracket 4i carries a unitary camera projector generally denoted by the numeral 42, the unit n Figure 2, and in detail longitudinal partial secti ure 3.

' Referring to Figure 3, the camera -projector 42 has a main'base or bed plate 43. A' stepp ed vertical sleeve 44 is secured in the front lend of the base 43 and has rotatably mounted therein, a second sleeve I! on the lower end of which is sement of the usual iris diaphragm (not shqwnL} is mounted in the barrel 41. l

A reversible motor 54, mounted on the bottom of the camera base N, has on its shaft 5 a worm 5| meshing with the gear ring it as shown in FigoninFigure 2. I A flexible shaft 51 connects the end of the motor shaft 55 to a revolution counter ll so a disposed that its counter numerals are in direct view from the front of the apparatus.

From the foregoing description it will be evi-% dent that when the motor BI is operated the worm It revolves the gear ring it and with it the sleeve 45. The barrel 41 being threaded insleeve 45 but restrained from rotation by"the stationary key 50, rotation of sleeve 45' feeds the barrel ll and with it the lens assembly 82 upward or downward depending on the directionof" tion of the lens position, so that by control of the motor 54 any given lens position may be accurately made or reproduced, the comparatively large numerals 59 being plainly visible at a distance from the device.

A lamp housing 62 is horizontally pivoted at 63 and normally engages the top of the central portion 50 in light-tight relationship. A condensing lens system 64 is secured in the bottom of the housing 62 in optical alignment with the projection or photographic lens 52. A lamp 65 is mounted in a socket G6 in the rear end of the housing 62. An inclined mirror 81 is adjustably secured to the upper front wall 88 of the housing in position to direct light from the lamp 65 to the condensing lens system 34, thence through the subassembly 6i and projection lens 52. Ventilation for the lamp 65 is provided by a pipe 59 leading up through the bottom of the housing 82 and suitable openings 10 in the rear thereof.

A light shield or hood H is pivoted at 12 to the carriage 4i, the front upper end 13 of the hood normally overlying the rear top of the lamp housing 62. A rod 14 is horizontally pivoted at 15 to the rear of the housing 62, while the rear end of the rod engages a socket 18 secured to the back of the hood 1 I.

When the housing 42 is swung upward and rearwardly on its pivots 63 to allow access to the sub-assembly 6i as hereinafter set forth, the rod 14 swings the hood 1| upwardly as illustrated in dot and dash lines, Figure 3, thus providing ample clearance between the top of the housing and the hood.

A motor 11 having a suitable speed-reducinggear head 18 is mounted in the base 43 and is adapted to drive the shaft 19 of the sub-assembly OI through an extension shaft 40 and a jaw coupling 8i. The extension shaft 89 carries two cams 82 and 83, shown in detail in Figures 5 and 6, these cams being adapted to respectively control switches 94 and 95 for purposes hereinafter set forth. Rubber vibration dampers 11* are provided in the mounting of motor 11.

The column 40 is provided with a longitudinal key 86 fitting in the rear portion of the carriage 4i, thereby preventing any swinging motion of the carriage and camera-projector about the column.

A reversible motor 81, mounted under the frame 30, is provided with a worm-gear speed reducer 88 carrying on its output shaft 89 a sprocket 90. A roller chain 9i is secured to the upper portion of the carriage 4I and extends up ward therefrom and over an idler sprocket 92 on the top of the column 40, thence downward through the interior of the column and around a second idler sprocket 93 to the drive'sprocket 90, and thence via a third idler sprocket 94 to a turnbuckle 95 secured to the bottom of the carriage 4 I.

When the motor 81 is operated to drive the chain 9I the carriage and camera-projector assembly is raised or lowered along the column 40, and as the worm speed reducer 89 is of the irreversible drive type the latter acts as a lock to hold the carriage at any point of elevation when the motor is stopped. The tum-buckle 95 is operable to take up any slack in the chain. A heavy weight 9| is secured to the chain 9i inside the column 40 to serve as a counter-balance for the greater part of the weight of the carriage and camera-projector.

A measuring tape 96 has its free end clipped'to the chain 9| at 91 just below the turn-buckle 95, the tape extending downward in front of the chain through a slot 98 in the table 34 and to a spring actuated retracting reel 99 of any suitable type secured under the table.

As the mechanisms of such reels are well known and form per se no part of the present invention, no further description is required herein. It is evident, however, that as the carriage is moved up or down the tape 94 unreels or re-reels through the slot 99 and the figures I00 (see also Figure 4) thereon serve as a visual indication of the height of the camera-projector above the table 14 as illustrated in Figure 4.

A pair of film housings or magazines III and I02 (Figure 2) are attached respectively to the left and right sides of the middle portion N of the camera-projector 42. The magazines III and I02 are provided with detachable front closures I09 and I04, and contain suitable film reels adapted to carry a film I01 threaded between them through the control and shutter sub-assembly 6| Referring to Figure 1, the table skirt I14 carries. on its front face left-hand and right-hand control panels I15 and I16 respectively, these panels being hown in enlarged detail in Figures 7 and 8.

The panel I 15 has mounted therein two singlepole single-throw toggle switches I11 and Ill two reversing switches I19 and I", two momentary contact push-button switches iii and III, and a time-switch I ll of any suitable type provided with a trip or release button I 84.

The panel I19 has mounted thereon two toggle switches Ill and I". Mounted on the post or standard 39 behind the panel I19 is a variable voltage transformer I91 having a rotary control shaft Ill. The shaft Ill extends outward through an enlarged hole I99 in the panel I19 so as not to touch the latter, and is provided with an operating handle I" in front of the panel.

Referring to Figure 1, a pair of brackets III and I92, secured to the rear portion of the frame 30 and extending angularly outward and upward therefrom, have forwardly-extending horizontal portions I93, each carrying a plurality of incandescent light I94. The lights I94 are directed downwardly and inwardly so as to provide even illumination throughout the entire upper area of the table 34, while at the same time the angles of illumination are such that no direct reflection of light can enter the lens of the camera 42.

A pair of normally closed limit switches Ill and I96 (Figure 3) are mounted in the rear portion of the carriage 4|. These switches, which are preferably of the type known as microswitches, are provided with operating lever rollers I91 and I99 adapted to engage and be actuated by abutments I99 and 200 respectively secured to the upper and lower rear extremities of the column key 88.

A momentary contact foot switch "I (Figures 1, and 10) is movably disposed under the table 84 and is provided with a flexible cable 202 connecting it to the main apparatus in the electrical manner hereinafter explained in connection with the wiring diagram (Figure 11). A small signal light 203, preferably equipped with a red bulb, is mounted at the rear of the table 84.

Referring to the typical wiring diagram (Figure 11), the numerals 204 and 205 designate the conductors of a suitable source of A.-C. current supply, leading into themain or line switch Ill, thence to distributing conductors 208 and 291.

Branches 208 and 209 lead to manual switch I hereinafter termed the light switch. From the output poles of the switch I99 wires 2I9'and 2 are connected to the variable transformer I91. The lamps I94 (Figure 1) are connected in parallel between conductors 2I2 and 212- from the output'terminals of the transformer I91.

It will be seen from the above description that when the switches I99 and I91 are closed, the lamps I94 draw current and are illuminated, the voltage and consequently the intensity of the illumination being adjustable by means of the variable transformer I91.

The reversing switch I19 is of the three-pole double throw construction with a central "01! position. The switch ha upper and lower contact points 2I9, 2, 2i! and 2I9, 2I1, 2I9, respectively adapted to be alternately engaged by poles 2I9, 229 and 22I, poles 2I9 and 229 being electrically joined together. Contacts 2 and M9 are respectively cross connected in the usual manner with contacts 2I1 and 2I9 for reversing the current direction through field connectors 222 and 229 leading to the elevating motor 91. Poles 229 and 22I have leads 224 and 229 comprising armature connections to the motor 91. Pole 22I is also connected via the normally open pushbutton switch I9I with the distributing conductor 299. Poles 2i! and 2I9 are connected to the second conductor 291 respectively via the normally closed limit switches I99 and I99.

.When the switch I19 is thrown to upper position and the push-button switch I ll is closed, the connection from conductor 299 is completed via switch "I, pole 22I, to the motor-armature lead 229, also via pole 22I and contact 2I9 to the field lead 229. At the same time current flows from the conductor 291 via limit switch I99, contact 2I9 and pole 2" to the pole 229, thence to the second armature lead 224, and via contact 2I4 to the second field lead 222. By this means the motor is energized to raise the carriage 4| (Figure 3). 1

When the switch I19 is thrown to downward position, the current connections to the armature leads 224 and 229 are the same as'described except that the pole 2I9 receives current from conductor 291 via limit switch I99 and lower contact 2I9 without any change in polarity. However, the field leads 222 and 229 now receive their current from poles 22I and 229 respectively through the cross connected contacts 2I9 and 2" respectivehr. The motor field is thereby reversed, causing the motor 91 to revolve in the reverse direction and lower the carriage 4I.

If during upward driving operation of the motor 91 the limit switch I99 is opened, the described supply from conductor 291 is broken, causing the.

motor 91 to stop. Thereafter, current can be restored only by throwing the switch downward to complete the connection through the second or lower limit switch I99, whereupon closure of the button switch I9I again energizes the motor in the downward driving direction.

Similarly, if the lower limit I99 switch is opened to stop the motor, the latter can onlybe energized after throwing the switch I19 to upward driving position.

By the above described means, it will be seen that engagement of either limit switch with its operatingabutment I99 or 299 stops the progress of the carriage H, but the latter may be thereafter moved away from the extreme or limitposition after reversing the switch I19.

Returning to Figure 11, a branch lead 229 connects one side of the projection lamp 99 with the distributing conductor, while the other side of low-speed geared connected on one side via a lead 23I ductor 296. A wire 234, from the second side of.

the lamp is adapted to be connected via a lead 221, the time switch I93, and a second lead 229 to the second distributing conductor 291. The manual switch I19 (Figure 7) is shunted across the time switch I93 by means of wires 229 and 239. Thus when switch I19 is closed, the lamp 95 figranains energized irrespective of the time switch The time switch I93 is preferably of th enknown electrically actuated type, a branch 229- being provided to supply a current connection from 299 to the actuating mechanism under contrOl of the button m; The shutter mom 11 is to the conthe motor 11, is connected to the normally open camswitch 94 (Figures 3 and 5) thence via lead 235, the toggle switch I11 (Figure 7), and a lead 299 to the conductor 291. Also, from the other or second side of the motor 11, a wire 232 is connected to the normally open foot which latter isin turn connected via lead 233 to the lead 235.. i

- From the above connections, it is evident that the motor "may be energized through either one of two parallel circuit-closing means that is via the foot-switch 29I 'or via the cam switch 94 and manual switch I11, which latter is normally kept closed during the photographing operation. The cam 92, as previously setforth, is secured onthe 11 output shaft 99 ,of ,themotor allows the switch 94 to remain open only in normal or stop position as shown.

When the foot-switch 29I is mqmenmn'yflchsato start themotor 11, the initial cam 92 also closes the switch 94 after opening of movement of the the cam 92 again allows the switch 94 the circuit and stop the motor 11.

Ifthe toggle switch I11 is opened, as; in pro.- Jecti0n operations hereinaftendescribed, it is evident that no holding circuit can be established by remains;

the signal light 293 to light up during that portion of the revolution of shaft 99 when the previously 1 described shutter I99 is open.

The focusing motor 94 is connected through;

the reversing switch I99 with the conductors 299 and 291, th normally open push-button switch I92 being interposed in the circuit connection from conductor 299 As the operation and wiring of suchreversing switchesare well known and have previously been described in connection with elevating motor 91, further detailed description thereof is believed unnecessary repetition herein; it is evident that throwing the switch I99 to upper or lower position conditions the motor circuit for operation of the motor in either desired direction under control or the push-button swltchl82. The operation is as follows:

Phot raphy first places a frame or developed film I91 in posi switch 29I,

The contour of the cam 92 is such that it and holds itv closed the foot switch, thus keepingthe motor energized and causing it to drive the shaft 99 throughout one complete revolution, whereupon ,to break-- tion on th film-gate, the housing 52 having been previously swung upward and open on its pivots 63 to allow access to the interior of the subassembly ii. The housing 62 is closed down, and the "enlarger" switch I18 is closed, thereby turning on the projection lamp 65. The operator next depresses the foot-switch 20 I, starting the shutter control motor 11 and allowing the latter to run under control of the cam-switch 04 until the shutter reaches wide-open position. At this point the manual switch I11 is opened to stop the motor 11, leaving the shutter in open position.

The shutter I68 being open, light passes from the lamp to the inclined mirror 61, thence downward through the condensing lens system 54, the shutter sub-assembly SI and the film therein, and the lens 52, an image of the developed film frame being projected on the table 34 or on a sheet of material spread thereon. The operator then manipulates the elevator switch I19 and push-button I8I to lower or raise the carriage and camera-projector by means of the motor 81 until the projected image covers the desired area. The operator similarly manipulates the switches I and I82, to adjust the lens 52 by means of the focusing motor 54 until the image is sharply focused. The foregoing field and focus adjustments may be made with the image projected directly on the sheet to be photographed or on a suitable blank sheet of proper size.

The document, drawing, or the like having been secured to the table 34 by any suitable means such as tacks, tape or weighted retainers, and the previously described field and focus adjustments having been made, the lamp 65 is extinguished by opening the switch I18 and the shut-' ter switch I11 is closed, the latter causing the motor 11 to be energized through the camswitch 04 as previously described. The motor 11 runs until the cam 82 opens the switch 84 in normal position as shown in Figure 5, thereby closing the shutter. The operator replaces the developed film with unexposed film, threading the latter from the reel I05, through the control subassembly SI, as shown in Figures 9 and 10, and

to the take-up reel I06; the housing 62 is again lowered into closed position to exclude light.

It will be understood the above described preparatory field and focus setting need be performed only once, at the beginning of a series of photographic recordings of similar size.

To photograph the document spread on the table 34 the lights I84 are turned on by closing the switch I85 and if required the intensity of illumination is adjusted by means of the variable transformer I01, either to a pre-determined setting of the handle I or by use of any suitable light meter. The operator then momentarily closes the foot-switch 20I to start the shutter motor 11, the cam-switch l4 thereafter causing the motor to drive the shaft 80 until one complete revolution is completed as previously set Figure 3, thus effects the exposure and conditions the apparatus for the next exposure. The operator removes the first document or other subject photographed from the table 34, places the second in the same position, and again depresses the foot-switch "I to photograph the second subject, and proceeds in the manner described to record the desired series of subjects on successive frames of the film I01.

A noted previously, an entire series of subjects may be photographed after a single initial setting of the field and focus. However, once a certain desired field and focus setting have been arrived at for a given size of subject, no initial projection is necessary thereafter in order to arrive at this setting for later recordings, due to the provision of the height scale 96, Figures 3 and 4. and the counter or register 58, Figure 2. When the operator has initially arrived at the proper field and focal settings as described, he may observe and note down the readings of the scale and counter 58, the figures of both being readily visible from the operating position in front of the table. Thereafter, when it is desired to photograph further subjects of the size or series noted, or to reproduce the subjects by projection as hereinafter described, it is only necessary to operate the elevating and focusing switching means until .the previously noted height and focal readings appear on the scale 95 and counter 59. Similarly, subjects of different areas may be photographed in series without intermediate test setting or focusing, simply by manipulating the elevating and focusing controls to bring the scale and counter readings to previously determined proper figures for the various sized subjects. In case of series photographing of widely differing fields or areas, and consequent lens distance, it may also be desirable to vary the intensity of the illumination by manipulation of the transformer control handle I90 as previously described.

It will be noted that all the foregoing operations may be effected by the user from a single position in front of table 34, the normal functions of setting camera height, setting the focus, setting the illumination, making the exposure, and resetting the film being carried out by remote control from the panels I15 and I10. Even the manual operation of changing or adjusting the film I01 in the camera may be carried out from the same position, since the camera may be lowered to extreme bottom position directly in front of the operator, the proper original height being afterward restored, as previously noted, from the scale 96. It is obvious that provision of the described complete remote control from a single position adapts the device to rapid and easy operation with a minimum of fatigue for the user.

Reproduction When it is desired to reproduce previously photographed subjects, the developed film carrying the images is threaded into the cameraprojector 42. The projection lamp i5 is turned on,

' the shutter is again opened by manipulation of ,switches I11 and MI, and the proper camera height and focus are arrived at either by direct test projection on a blank sheet on the table 34 or by setting to height and focal indicating figures previously noted at the time of photographing the particular subject to be reproduced. The time switch I83 having been set for the desired period of exposure, the switch I18 is opened to extinguish the lamp 65 and a suitable sheet of sensitized paper or the like is secured in proper position on the table 34.

The time switch in is tripped by means of its button I, the switch closing and remaining closed for the predetermined time in the usual manner of such switches. The lamp 65 is thereby illuminated during the pre-determinedperiod, during which period the enlarged image from the film )1 is projected on the sensitized sheet. When the time-switch I83 has again extinguished the lamp 65 the sensitized sheet is removed for development and/ or fixing in the usual manner. In case a succeeding image on the film strip is to be reproduced, switches I11 and 2M are operated until the shutter motor IT has closed and again reopened the shutter I68, during which operation the him has been advanced oneframe in the manner previously described, after which a second sensitized sheet is placed in position and the second projection exposure made as set forth.

In case it is desired to make more than one print from the same film frame, the operator simply changes the sensitized sheets and effects the exposures by repeated trippings of the time switch I83 without intermediate closings of the shutter I.

All the described reproducing operations are carried out from the single operating position,

and except of course for changing the sensitizedpaper, all are done by remote control, with the same advantages of speed, ease and precision noted with respect to recording.

While the apparatus is adapted to reproduction in the precise original size, it is obvious that enlargement or reduction in the reproduction may readily be made by proper setting of cameraprojector height and focus.

From the foregoing description it will be seen that the invention makes possible the photographic recording and reproduction with maximum rapidity, precision and accuracy, guesswork being eliminated. The accuracy is augmented by the fact that reproduction takes place by projection through the same lens and, if desired, with the'identical setting used in the original photographic recording. Thus any defects, such as optical aberration or blurs impressed on the film for any reason, even such as slight optical defects in the lens, are automatically cancelled out and corrected by reversal in the projection through the same lens; the results are thus uniformly sharp reproductions of the originals.

A convenience outlet 240, connected to the conductors 208 and 201, Figure 11, may be provided at any suitable location on the device, for supplying current to any auxiliary electrical apparatus, such as extension lights or the like, which it may be desired to use in connection with the apparatus.

While the invention has been described in preferred form it is not limited to the precise structures illustrated, as various modifications and changes may be made without departing from the scope of the appended claims.

What is claimed is:

1. In a device of the character described, a casing, a lens in said casing and adapted to be moved therein on the line of the optical axis of said lens to focus the same, rotary means to move said lens on said line, a reversible motor,

positive speed reducing means connecting said motor to said rotary focusing means, a counter spaced apart from said motor and said casing and having visual characters indicating predetermined increments of movement of said lens, I

and a flexible shaft connected to said motor and to said counter for positively operating the latter, said characters being visible outside the device.

2. In a-deyice of the character described, in combination, a lens, means to move said lens to focus the same, said means including a revrrsible motor, a visual indicator spaced apart from said lens and said motor and directly connected to the latter by means of a flexible shaft, said visual indicator including numerical counter members I cumulatively movable by said motor in definite digital increments, each incremental change in the indicating position of said visual indicator being a calibrated indication of a definite incremental movement of said lens, whereby said visual indicator may present a predetermined definite digital combination for each focal position of said lens. V

3. In a camera-projector, amain horizontal base having a stepped vertical hole formed therein the center of which lies on the optical axis of said camera-projector, a stepped tubular boss mounted in said hole and secured to said base, a shouldered tube mounted in said tubular boss,

a worm-gear ring secured to said shouldered tube, a cylindrical barrel mounted in said shouldered tube and having means associated therewith for causing said barrel to move longitudinally as said shouldered tube is rotated, a lens carried by said barrel, a reversible motor, a worm driven by said motor and connected to said worm gear ring, a counter carrying characters indicating increments of movement of said lens, and a flexible shaft having one end connected to said counter and the other end connected to said motor.

4. In a camera-projector, a main horizontal base forming a portion of the frame of said camera-projector and having a stepped vertical hole formed therein the center of which lies on the optical axis of said camera-projector, a

stepped tubular boss in said hole and fixedly secured to said base, a shouldered tube mounted in said tubular boss and having its shoulder en-.

gaging the step in said tubular boss, a worm gear ring secured to'said shouldered tube and movable therewith, a cylindrical barrel mounted in said shouldered tube and having means associated therewith for causing said barrel to move longitudinally as said worm-gear ring is rotated, a lens-cell secured to said barrel, a reversible electrical motor, said motor having a shaft extending therefrom, a worm secured to said shaft and meshed with said worm-gear ring, thereby driving the latter at a reduced rate of speed, a counter spaced apart from said'frame and said motor, said counter having visual characters for indicating increments of movement of said lens cell, and a flexible shaft connected to said motor and to said counter thereby. making it necessary for the axes of the motor and the counter to coincide.

- VERNEUR E. PRATT. 

